Separate-type air conditioners popular in the marketplace include, for example, units disclosed in Patent Literature 1 (Japanese Laid-open Patent Application No. 2000-111123). This air conditioner is designed such that signal intercommunication between an indoor controller and an outdoor controller takes place through a signal transmission communication line; the outdoor controller is connected via opening/closing means to a power line inside the outdoor unit, and even when the opening/closing means is open and the outdoor controller is stopped, startup power can be fed from the indoor unit side to the outdoor unit side through the signal transmission communication line. That is, with this configuration, the feed of power to the outdoor unit side during standby is cut off, and standby power is reduced.
On the other hand, with a separate-type air conditioner having a thermostat, an indoor unit, and an outdoor unit, each of the air conditioning modes are controlled by switching the thermostat to either a state of “outputting” or a state of “not outputting” a control signal to the indoor unit and the outdoor unit.